In their recently published paper, the scientists said solar energy is an important alternative to fossil fuels, yet there are still limitations to the technology, namely that solar power systems aren’t as reliable at night. Certain technology sidesteps this problem by using hydrogen, H2, to store solar energy “in the form of chemical energy“. This allows fuel cells to produce electricity at all hours of the day. But H2 comes with its own issues: typically it has to be compressed or cooled to a liquid state to be stored efficiently.

That’s where this new research comes in. The scientists discovered a way to obtain H2O2 from seawater using sunlight. That compound has an advantage over H2 because it can be stored more simply and safely. So why haven’t engineers used H2O2 in the past? According to Phys.org, until this new research came to light, there wasn’t a way to produce liquid H2O2 via sunlight, which is more efficient than other ways scientists can obtain liquid H2O2.

This new method doesn’t offer a complete solution. The new fuel cells aren’t yet as efficient as traditional solar cells, but the scientists are working to fix that. Engineer Shunichi Fukuzumi of Osaka University told Phys.org, “In the future, we plan to work on developing a method for the low-cost, large-scale production of H2O2 from seawater. This may replace the current high-cost production of H2O2 from H2 (from mainly natural gas) and O2.” To do this, they’ll search for “better materials” to use in the photoelectrochemical cell they’ve designed as well as other ways to reduce costs.